/* ===================

AX2E (AXESCON XACML 2.0 Engine) is the Java authorization engine, which implements OASIS XACML 2.0 standard.
Copyright (C) 2007 AXESCON LLC

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA


Contact: AXESCON LLC - info{at}axescon.com

 =================== */
package axescon.xacml.samples.customfn;

import axescon.xacml.api.*;
import axescon.xacml.model.shared.attr.IntegerAttribute;

import java.util.Calendar;
import java.util.GregorianCalendar;

/**
 * @author Date: Sep 28, 2005
 *         Responsibilities: demonstrate how to create a custom function.
 * This function takes one integer argument - year in the past - and returns true if
 * even years passed since that year until now,; otherwise it returns false.
 * For instance, if the argument is 2001, then in 2006 the function should return false.
 */
public class FnEvenYearsPassed extends AbstractFn  {

    {
        dataTypes = new Class[]{IntegerAttribute.class};
    }

    public void setDataTypes(Class[] dataTypes) throws XacmlException {
        // mute this method
    }

    public int getArgTypeListLength() {
        return 1;
    }

    public Liquid exec(Liquid[] args) {
        int thisYear = new GregorianCalendar().get(Calendar.YEAR);
        long argYear = ((IntegerAttribute)args[0].getSingularUnsafe()).getValue();
        return returnBoolean( (thisYear - argYear) % 2==0 );
    }

    public Class getReturnDataType() {
        return super.getBooleanReturnDataType();
    }

}
